net: fib_notifier: don't return positive values on fib registration

The function fib6_walk_continue() cannot return a positive value when
called from register_fib_notifier(), but ignoring causes static analyzer to
generate warnings in users of register_fib_notifier() that try to convert
returned error code to pointer with ERR_PTR(). Handle such case by
explicitly checking for positive error values and converting them to
-EINVAL in fib6_tables_dump().

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Suggested-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index f43e27555725115aa0a0ed4ba3a34869e3fc491f..ef9d022e693f047ef2e86e6ec370b1bfcfc28ad1 100644 (file)
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -499,7 +499,7 @@ int fib6_tables_dump(struct net *net, struct notifier_block *nb,
 
                hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
                        err = fib6_table_dump(net, tb, w);
-                       if (err < 0)
+                       if (err)
                                goto out;
                }
        }
@@ -507,7 +507,8 @@ int fib6_tables_dump(struct net *net, struct notifier_block *nb,
 out:
        kfree(w);
 
-       return err;
+       /* The tree traversal function should never return a positive value. */
+       return err > 0 ? -EINVAL : err;
 }
 
 static int fib6_dump_node(struct fib6_walker *w)